1. Field of the Invention
This invention relates generally to the provision, as part of the building construction process, of sills or hobs for the fixing of windows, curtain walls and the like to cast-in-situ concrete slabs. More particularly, it relates to moulds for the casting of such sills or hobs onto or integrally with cast in-situ concrete building slabs.
2. Description of the Related Art
Any discussion of the related art throughout the specification should in no way be considered as an admission that such related art is widely known or forms part of common general knowledge in the field.
Particularly in the construction of multi-story buildings, it is common to provide raised sills or hobs of some form to cast in-situ concrete slabs. Such sills or hobs act as supports for building elements such as window frames, curtain wall panels and the like, providing a watertight barrier beneath such building elements to prevent the ingress of rain water and condensation. Said building elements may incorporate lower frames or sills that bear directly upon and are sealed to a supporting surface such as a cast in-situ concrete slab. These commonly take the form of simple or complex metal sections or solid timber sections. In other applications, separate sills or hobs of similar form are sealing fixed to a said supporting surface and said building elements are fixed to and supported by said sills or hobs. In yet other applications, concrete sills or hobs are formed on said cast in-situ concrete slabs to support said window frames, curtain wall panels and the like. In these applications, long box moulds which are more or less open at the top and bottom are fixed in appropriate positions to concrete slabs, filled with concrete and the concrete allowed to cure. Said sills or hobs are then waterproofed appropriately and said building elements then fixed to them. The separate forming of said sills or hobs on cast in-situ concrete slabs is inefficient and time consuming, requiring the re-attendance of several building trades personnel to a building site to accurately measure up and fix said moulds in position and then to fill them with concrete. Additionally, irregularities in the trowelled surfaces of said cast in-situ concrete slabs may require the removal of concrete in order for said moulds to be set at the correct level. When it is considered that a multi-story building may require several thousand lineal meters of such sills or hobs, the magnitude of the inefficiency and loss of time will be appreciated.